The present invention relates to polyamide compositions and therapies for treatment of cells and tissues infected with double stranded DNA viruses, for example, human papillomaviruses (HPV) and/or polyomaviruses (PyV).
A significant part of the viral life cycle of many DNA viruses has them maintained as double-stranded, closed circular, supercoiled, chromatinized DNAs within the nucleus. Among these viruses are a number of types that cause a significant disease burden including papillomaviruses, polyomaviruses, Epstein Barr virus (EBV), and hepatitis B virus (HBV), a member of the genus Orthohepadnavirus. 
Polyomaviruses (PyV) are a family of small (˜5 KB), non-enveloped DNA viruses that occupy a broad replicative niche in vertebrates from birds to humans, but individually have a narrow species tropism. Simian virus 40 (SV40), an archetypal PyV was first discovered as a tumor-inducing virus in rhesus monkey kidney cells cultures (1) and subsequently became an important tool for studying DNA replication, repair, and oncogenesis. Recent years have seen considerable growth of the number of known polyomaviruses, with human polyomaviruses (HPyV) now numbering over ten (2). HPyV are suspected etiological agents in a number of cancers, but only MCPyV has been definitively associated with the rare and aggressive Merkel Cell carcinoma (3).
PyV often persist as latent infections without causing disease, but reactivation of the infection may lead to disease in a variety of tissues. For example, reactivation of PyV in immunocompromised patients is a growing area of concern. BK polyomavirus (BKV) is the major cause of polyomavirus-associated nephropathy (PyVAN) causing 1-15% of kidney transplant patients to be at risk of premature allograft failure (4). There are a growing number of PyVAN patients due to increases in the numbers of renal transplants and the development of more effective immunosuppressive drugs (5). Likewise, 10-25% of bone marrow transplant (BMT) patients are susceptible to hemorrhagic cystitis of the bladder and lower urinary tract that is largely attributable to BKV reactivation due to immunosuppression (6).
Progressive multifocal leukoencephalopathy (PML) is a rare, but typically fatal, inflammation of the white matter of the brain in multiple locations that is attributable to JC polyomavirus (JCV) (7). PML is typically associated with JCV reactivation in severely immunocompromised patients such as those receiving immunosuppressive therapy following transplant, following chemotherapy, or in those with AIDS. Other HPyV are also associated with morbidity following reactivated in immunocompromised patients. Merkel cell polyomavirus (MCPyV), for example, has been implicated as the etiological agent in Merkel cell carcinoma, a cancer with a strikingly high incidence in AIDS; chronic lymphocytic leukemia (CLL) patients; and in immunosuppressed organ transplant patients, including but not limited to bone marrow transplant recipients (7). There are currently few antiviral treatment options for polyomaviruses and so antiviral therapies would be an important advancement for diseases associated with these viruses (7).
HBV is a small (˜3.2 KB), enveloped DNA virus that infects hepatocytes and replicates by way of an RNA intermediate (8). The encapsidated viral genome consists of 3.2 kB of relaxed, circular DNA which is converted to covalently, closed, circular DNA (cccDNA) upon its translocation to the nucleus. Chronic infection by HBV contributes to a number of diseases of the liver including hepatitis with progression to cirrhosis and hepatocellular carcinoma (9). More than 240 million people are infected with HBV, and 780,000 people die annually due to the consequences of HBV infection (10). There is no specific treatment for HBV although some patients can be treated with Interferon or antiviral agents to slow the progression of the disease. Seven drugs have been licensed by the FDA, to date, for the treatment of chronic hepatitis B infection: interferon-alpha and pegylated interferon-alpha, three nucleoside analogs (lamivudine, entecavir and telbivudine) and two nucleotide analog prodrugs (adefovir dipivoxil and tenofovir disoproxil fumarate) (11). Current antiviral agents can control but not eliminate HBV because HBV establishes a stable nuclear cccDNA. These drugs have little impact upon the levels of cccDNA and, therefore, while helpful to control infection, have little effect upon long-term HBV persistence. Strategies to eliminate cccDNA may prove very helpful for treatment of hepatitis due to chronic HBV infection (12-14).
Human papillomavirus (HPV) is a small double-stranded DNA virus that colonizes various stratified epithelia like skin, oral and genital mucosa, and induces the formation of self-limiting benign tumors known as papillomas (warts) or condylomas. Most of these benign tumors naturally regress due to the influence of host immunological defenses. Some HPVs, however, have oncogenic potential and have been associated with certain types of cancers. See, Lorincz et al., Obstetrics & Gynecology, 79:328-337 (1992); Beaudenon et al., Nature, 321:246-249 (1986); and Holloway et al., Gynecol. One., 41:123-128 (1991).
HPV is the most prevalent, sexually transmitted virus. More than 35 HPV genotypes are known to be sexually transmitted, but a subset accounts for the majority of ano-genital infections. Among these most common HPV types are two forms with high risk for carcinogenic progression (HPV16 and HPV18), and two forms that cause the majority of genital warts (HPV6 and HPV11).
An estimated 5.5 million people become infected with HPV each year in the United States, and an estimated 20 million Americans are currently infected (Cates and et al., Lancet, 354, Suppl. SIV62, 1999). Approximately 75 percent of the male and female reproductive-age population has been infected with sexually transmitted HPV and, though the main public health risk to women is cervical cancer (Koutsky, Am. J. Med., 102(5A), 3-8, 1997), genital warts constitute an epidemic. Thus, millions of people in the U.S. alone require treatment each year. It is important to note that PAP smears represent the largest public health screening program in the world, and that the test is, essentially, a measure of HPV infection. One standard for managing a positive PAP smear is “follow up”. In general, no treatment is recommended unless an advanced stage of cervical dysplasia is observed (CDC Sexually Transmitted Diseases Treatment Guidelines, 2002).
Significant need exists in HPV positive subjects for effective HPV antiviral drugs. At present, no specific treatments exist for HPV or warts. Aldara™ (Imiquimod), an immunomodulator used for treating external genital warts, is the most successful treatment on the market. An effective, specific HPV treatment has the potential to significantly improve upon, and effectively compete with, Imiquimod.
The majority of human cervical carcinomas (95%) contain and express HPV DNA and it is the expression of two viral oncoproteins, E6 and E7 that appears to be critical for cellular transformation and maintenance of the transformed state. Specifically, four HPV types (HPV-16, HPV-18, HPV-31, and HPV-45) have been connected to 75-93% of the cases of cervical cancer in the United States. It has been estimated that perhaps twenty percent (20%) of all cancer deaths in women worldwide are from cancers that are associated with HPV.
HPV also causes anal cancer, with about 85 percent of all cases caused by HPV-16. HPV types 16 and 18 have also been found to cause close to half of vaginal, vulvar, and penile cancers.
Most recently, HPV infections have been found to cause cancer of the oropharynx, which is the middle part of the throat including the soft palate, the base of the tongue, and the tonsils. In the United States, more than half of the cancers diagnosed in the oropharynx are linked to HPV-16.
HPVs can be further classified as either high or low risk based on the clinical lesions with which they are associated or the relative propensity for these lesions to progress to cancer. Low risk cutaneous types, such as HPV types HPV-1, HPV-2, HPV-3, HPV-4, HPV-5, HPV-7, HPV-8, and HPV-9 cause common warts (verrucae vulgaris), plantar warts (verrucae plantaris), mosaic warts, flat warts (verrucae plane), and butcher warts. Furthermore, HPV types HPV-6 and HPV-11 cause warts of the external genitalia, anus and cervix. High-risk types, such as HPV-16, HPV-18, HPV-31, HPV-33 and HPV45 are particularly common in intraepithelial carcinomas, neoplasias and cancers. In particular, the genomes of two HPV types, HPV-16 and HPV-18, have been found to be associated with about 70 invasive carcinomas of the uterine cervix, as well as cancers of the oro-pharynx, anus, and other mucosal tissues.
Current treatment for HPV infection is extremely limited. Management normally involves physical destruction of the wart by surgical, cryosurgical, chemical, or laser removal of infected tissue. Some of these current treatments, like laser removal and surgery, are expensive and require the use of anesthesia to numb the area to be treated. Cryosurgical removal requires the use of special equipment. Furthermore, most subjects experience moderate pain during and after the procedure.
Topical creams and solutions such as preparations of 5-fluorouracil, Imiquimod, cidofovir, formaldehyde, glutaral, cimetidine, tricholoroacetic acid, bleomycin, podofilox and podophyllum preparations have also been used. (Reichman in Harrison's 7 Principles of Internal Medicine, 13th Ed. (Isselbacher et al., eds.); McGraw-Hill, Inc., NY (1993) pp. 801-803). Recurrence after these treatments, however, is common, most likely because the virus remains latent within the host epithelial cells. Therefore, subsequent repetitive treatments must be used, which can destroy healthy tissue. These treatments are not available or approved for treatment of cervical infections.
Interferon has also been employed as a treatment for persistent HPV infections and warts. However, its effectiveness is limited. Chang et al. (2002) Journal of Virology 76: 8864-74, found some cells infected with HPV genomes became resistant to interferon treatment after only a few applications. See also Cowsert (1994) Intervirol. 37:226-230; Bornstein et al. (1993) Obstetrics Gynecol. Sur. 4504:252-260; Browder et al. (1992) Ann. Pharmacother. 26:42-45.
Thus, there is a need for therapeutics for treating a number of diseases and conditions as outlined herein.